Centrifugal blowers typically include impellers having a plurality of blades that redirect an incoming airflow toward a radial direction as the airflow moves from the impeller inlet to the impeller outlet. The blades are typically attached to a hub for rotation therewith. An electric motor rotates the impeller at the required speed. The electric motor requires cooling and therefore has an airflow path through the motor.
In automotive climate control applications (i.e., heating, ventilation, and air conditioning), water can enter the inlet of a climate control blower assembly. The water must be prevented from propagating from the blower inlet to the inner workings of the electric motor. Some previous methods to prevent water from entering the motor have been unsuccessful; others, while successful, require the motor cooling air path to be created by joining the blower assembly to the main climate control module that includes the volute.
Other cooling air paths involve positioning the cooling hole or inlet high in the volute, just downstream of the volute tongue. The path then turns downward towards the motor flange where the motor flange assembles to the volute. The motor flange and a cover/cap piece then form the rest of the air path towards the bottom of the motor. The high position of the cooling path inlet is effective at preventing water from entering, but the cooling path design requires design details in both the volute and the blower assembly.